Hair Remover

Hair removers, or depilatories, are products designed to chemically or
physically remove undesirable hair from areas on the body. Hair removers
are made by mixing together the appropriate raw materials in large
stainless steel tanks and then filling them into individual packages. In
use for thousands of years, they continue to be an important part of many
people's everyday hygiene. Currently, new hair removers are being
investigated which are less irritating, more effective, and longer
lasting.

Background

Epilatories were the first type of hair removers. The most common of these
products is an epilating wax. This product is heated and spread on the
skin in the desired area. It is then allowed to cool and harden. The mass
of wax is then rapidly removed, pulling with it about 80% of the hairs. It
is a slightly painful procedure and a mild anti-+ septic is typically
applied to protect against skin irritation. Epilatories have not been
widely used by individual consumers, how-ever they are popular in beauty
salons.

While epilatories continue to be an important method of hair removal,
depilatories are much more common in personal care. Depilatories rely on a
chemical reaction between materials in the formula with components of the
hair. When the depilatory is applied to the skin, a component in the
product, such as thioglycolic acid, reacts with the protein in the hair
and weakens it. The hair can then be removed from the skin by gentle
wiping, scraping, or rinsing. This is effective on any part of the hair
structure that is above the level of the skin.

The compounds in the depilatories, which react with hair, also react with
protein in the skin, albeit at a much slower rate. For this reason,
depilatories must be left on the skin for only a short while. The
manufacturers of depilatories realize this and strive to develop formulas,
which have only minimal negative effects on skin. Typically, if a consumer
follows the directions as stated on the package, no problems will arise.
Epilatories generally will not have a negative effect other than physical
irritation on skin since they do not rely on a chemical reaction to
function properly.

The first step in producing a hair remover, or any personal care product
for that matter, is developing a formula. Cosmetic chemists use their
knowledge of standard cosmetic ingredients, consumer research information
and various other types of information to construct their formulas. Since
hair removers can be sold in many different forms including creams, gels,
lotions, and aerosols, the formula must be adapted to the product form.
The formulas are first prepared in small beakers in the lab so aspects of
the formula can be evaluated. Tests for product effectiveness, stability,
and safety are all completed at this point. Other studies such as consumer
acceptance testing may also be completed.

History

Hair removal from various parts of the body has been an important part of
beauty for thousands of years. The earliest recorded use of hair removers
is found in ancient India where hair removal was highly desirable. This
society frequently used abrasive pastes and resinous plasters to
physically remove
hair. In the Middle East, a lime mixture was used for a similar purpose.
Other materials, such as antimony and arsenic compounds, were also used;
however, it is now known that these materials are quite toxic, and their
use has been discontinued.

The earliest hair removers used a method of hair removal known as
epilation, or physically pulling hair out. Common procedures included
using devices like tweezers to pull hair out selectively or waxes which
pulled hair out in large masses. Since hair removal by physical means was
often a painful experience, scientists worked on developing formulas,
which would chemically remove hair. Little progress was made in this area
until about 100 years ago when it was first reported that barium sulfide
was used for this purpose. A few years later a similar idea was patented
in the United States. Cream depilatories were first introduced in the
1920s and many more patents were issued during the 1930s. Thioglycolate
depilatories, which were first introduced in 1938, have become the most
important hair removers.

Raw Materials

There are many different materials that have been used in hair remover
formulas. Some of these materials are responsible for the hair removing
properties of the product while others are needed to improve the
product's aesthetics.

As suggested, depilatories and epilatories remove hair in a very different
manner. Obviously, they then require different compounds to function. A
standard epilatory may be composed of a wax such as beeswax and a sticky,
polymeric resin. The wax provides the setting action needed for peeling
the product off the skin and the resin helps bind the material to the
hair. The active ingredients used for depilatories include thioglycolate
salts and sulfides. Thioglycolate salts include materials such as calcium
thioglycolate and potassium thioglycolate. In an aqueous solution at the
proper pH, they are converted to an acid, which then affects the hair.
Sulfides such as barium sulfide or strontium sulfide are also used because
they react more rapidly than thioglycolates how-ever, they have other
characteristics which make them less appealing. Since pH is critical to
the proper performance of depilatories, ingredients such as sodium
hydroxide or calcium hydroxide, which adjust the pH, are included.

In addition to the hair removing ingredients, other compounds are
necessary to complete formulation. This includes diluents, emollients,
thickeners, fragrances, and colorants. Water is used most often as a
diluent for depilatories because it is compatible with a large range of
raw materials, non-irritating, and inexpensive. Since epilatories are
waxes, they are not compatible with water so mineral oil is typically used
as the diluent. Emollients are included in formulations to reduce the
harshness of the formula and improve the feel. Materials like oils,
silicones, and esters are all examples of commonly used emollients.
Depending on the product's form, a thickening agent may be
required. These materials are typically polymers, surfactants, or modified
clays. For aerosol products, a propellant is needed.

To improve the aesthetics of the formula, fragrances are included. These
fragrances must be specially designed to overcome the generally offensive
odor of the hair removal ingredients. For cream or lotion products,
emulsifiers are needed and dyes are used to modify the color. Various
other ingredients such as preservatives, antioxidants, extracts may also
be included.

Beyond the ingredients that go into the hair remover formula, packaging
components are another important raw material. Bottles are primarily used
and are made of plastics such as polyvinyl chloride (PVC) or high-density
polyethylene (HDPE). For aerosol products, a steel or aluminum can is
used. The outer graphics can be either directly silk screened on to the
package or an adhesive label can be applied.

The Manufacturing
Process

The process for making a hair remover can be divided into two steps.
First, a large batch of the product is made, and then it is filled into
the individual containers. While there are many different product forms
the hair remover may take such as creams, aerosols, or waxes, the
following description

will only outline the method for making a lotion depilatory.

Compounding

1 The bulk batches of depilatories are produced in a designated area of
the manufacturing plant. Plant workers follow a standard formula to make
batches, which can be over 3,000 gal (11,355 1). The tanks, which are
stainless steel, are equipped with a large mixer and a heating and
cooling system. The temperature and the mixer speed are both computer
controlled, so the compounder can modify them who is making the batch.

When the controls are set, the raw materials can be added. In most
formulas, water is added first by being pumped in at the appropriate
volume. The mixer is then turned on and the other raw materials are
added in the order called for in the formula. These raw materials are
either poured into the batch from bags or 55 gal (208.2 1) drums. As
each goes into the tank, it is thoroughly mixed. Depending on the
formula, the batch is heated and cooled as necessary to help the raw
materials combine more quickly. A typical 3,000 gal (11,355 1) batch
of depilatory may take anywhere from two to five hours to make.

Checking quality

2 After the batch is finished, the quality control department must test
it before it can be sent along for filling. Physical characteristics are
examined to ensure the batch conforms to the specifications outlined in
the formula instructions. Typical tests done on a depilatory batch
include viscosity

After being filled, the bottles are capped, labeled, and boxed for
shipment.

checks, pH determination, and appearance and odor evaluations. They may
also check the activity of the thioglycolate. If the batch does not meet
the ranges set for the specifications, sometimes adjustments to the
formula can be made. For instance if the pH is too low, a depilatory
will not function properly. Therefore, a certain amount of a base such
as sodium hydroxide could be added to adjust the pH. Salt can be added
to increase the thickness of many of these products. Fragrance and color
may also be adjusted at this point. After quality control approves the
batch, it is pumped out of the main batch tank into a holding tank where
it can be stored until it gets filled. From the holding tank it may be
pumped into a carousel-style, piston head filler.

Filling

3 The depilatory is filled on a filling line, which is a series of
machines that connected, by a conveyor belt system. At the start of the
filling line, empty bottles are put in a hopper. This hopper is a large
bin, which contains a device that can physically manipulate the bottles
so they are standing upright when they come out. From this
bottle-sorting hopper, they are moved along a conveyor belt to the
filling machine.

4 The filling machine contains a finished batch of depilatory. It is a
carousel is made up of a series of piston filling heads that are
programmed to deliver the correct amount of product into the bottles.
When a bottle passes under the filling machine, product is pumped into
it.

5 After being filled, the bottles are moved to the capping machine. Just
like the bottles, the caps are stored in a hopper that is designed to
physically align them in the right order. As the bottles move by, the
capping machine automatically attaches and tightens the caps.

6 Next, the bottles move to the labeling machines (if necessary) and
then on to
the boxing area. In the boxing area, the products are lined up and put
into boxes. The boxes are stacked onto pallets and hauled away in large
trucks to distributors. The entire filling process can produce more than
500 bottles per minute or more.

Quality Control

To produce a consistent product, quality control inspections are done
throughout the manufacturing process. At the start, the raw materials are
checked to ensure that they meet the manufacturer's specifications.
Typically, quality control chemists sample incoming raw materials and run
numerous tests before qualifying them. These tests may include checks for
appearance, pH, odor, or viscosity. More complex testing may also be
performed. During manufacture, the batch of hair remover is periodically
tested to make sure that a functional product will be produced.

While the product is being filled, quality inspectors are stationed along
the entire filling line. These workers watch the containers as they pass
by and pull off any which are defective. This includes those that are
inadequately filled, have misplaced labels, or otherwise damaged.
Regulations also require that samples be periodically checked for
microbial contamination during filling.

The Future

The market for hair removers is relatively small compared to other
personal care products such as shampoos or conditioners, so only minimal
research is currently being pursued. The focus of this research has been
on making products that are less irritating and more moisturizing to the
skin, lower in odor and more effective. Irritation is likely to always be
a problem for all depilatories that chemically alter proteins so
compounds, which weaken hair in other ways, may be developed. Beyond
depilatories and epilatories, new drugs could be developed which can
inhibit the growth of hair from follicles. This might represent a kind of
permanent hair remover.